已知0<a<π⼀2<B<π,cos(B-π⼀4)=1⼀3,sin(a+B)=4⼀5.(1)求cos(a+π⼀4)的值

已知0&lt;a&lt;π/2&lt;B&lt;π,cos(B-π/4)=1/3,sin(a+B)=4/5.(1)求cos(a+π/4)的值
2025-05-20 21:11:06
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